This invention relates to flexible sealed joints for conduits used to transfer a compressed gas, such as in an aircraft air duct system, wherein flexing of such joints is desirable for relieving high thermal and mechanical stresses and misalignment of connecting conduits.
Broadly speaking, flexible couplings for transferring a pressurized fluid between two conduits having at least some limited capability of relieving thermal and mechanical stresses have long been known and used in the prior art. See for example, U.S. Pat. No. 5,106,129 granted to L. A. Camacho et al. on Apr. 21, 1992 which discloses a coupling having a body portion which is both translatable in and out of a pair of collars located on the ends of opposing conduits and rotatable therein. The body portion can also be tilted between the two collars as when the centerlines of the two conduits are displaced relative to each other. U.S. Pat. No. 4,427,220 granted to M. S. Decker on Jan. 24, 1984 discloses a flexible joint for conduit which is used in jet engine air bleed duct systems.
A problem that has been encountered using the Decker joint is that the carbon rings used therein are readily subject to cracking and breakage with mechanical vibration of the joint. Further, in order to replace the rings, the joint must be removed from the air bleed system and sent to a suitably equipped repair station to open the joint and change the rings. It would be desirable to provide a sealed flexible coupling containing seal rings readily capable of withstanding long term exposure to mechanical and thermal stresses and vibrations without cracking and breakage. It would also be desirable to have a sealed flexible coupling which can readily be taken apart at the site of its use so that seal rings contained in the coupling can be easily replaced without the need to remove the coupling from its attached conduits to a remote repair station.
By means of the present invention, these and other problems encountered using flexible couplings known in the prior art can be eliminated.